PROJECT SUMMARY Endocrine disrupting chemicals (EDCs) in everyday environments and consumer products can interfere with the body's natural hormone signaling. Examples include some pesticides, fragrances, flame retardants, ingredients in plastics and personal care products, and highly fluorinated substances. While different levels of evidence are available for different chemicals, major scientific bodies now agree there is sufficient evidence of harmful health effects to recommend exposure reduction. The Endocrine Society found support for links to obesity, diabetes, male and female reproduction, cancer, thyroid disruption, and neurodevelopmental effects. To make personal and public decisions about EDCs, people need a functional understanding about these chemicals, including where they come from, how they enter the body and affect health, and options for reducing exposure. This information constitutes EDC environmental health literacy (EDC-EHL). Health literacy is a significant factor in health outcomes and disparities, and EHL is expected to similarly influence individual and population health by supporting positive health behavior. However, interviews with participants who were biomonitored for EDCs reveal only a partial understanding of these exposures, suggesting significant gaps in most people's EDC-EHL. Effective communications must fill these gaps and correct misconceptions while remaining grounded in people's existing knowledge and beliefs. To improve communications, this project will be the first effort to (1) define functional environmental health literacy about everyday EDC exposures and (2) develop and test methods for assessing EDC-EHL. Aim 1 will develop a mental model of EDC-EHL through a series of focus groups. Participants will include researchers and community partners conducting EDC studies, many of whom are supported by the National Institute of Environmental Health Sciences (NIEHS). This aim will establish goals for public EDC-EHL. Aim 2 will develop an interactive, web-based survey to quantitatively assess people's knowledge and beliefs in comparison with the model from Aim 1. The design will incorporate game-like elements, and participants will receive personalized feedback to stimulate curiosity and motivate completion. The survey will be hosted on LabintheWild, a proven online research platform for behavioral studies, and will be mobile-friendly, since smartphones provide internet access for many people. LabintheWild attracts participants via social media, and partnerships with community organizations and a major employer will improve representation among older, less educated, and racially diverse demographics. The target 1,500 responses will provide preliminary data about EDC-EHL in the general population, and future research can leverage the survey in studies of large representative samples, specific groups, or interventions. Results from both aims will inform effective communications about EDCs and health, meeting a need identified by medical societies and scientific panels and providing immediate guidance for outreach in NIEHS research centers.